Dental chair



(Nol Model.)

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R. G. WALLACE 8v C.. H. SNYDER.

DENTAL CHAIR.

A Patented Sept; 9,1884.

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(No Model.) 2 shetsf-sheen 2.

R. G. WALLACE & C. E. SNYDER.

DENTAL GHAIB.. No. 304,876. Patented Sept. 9; 1884.

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Unire rarns artnr FFECE@ ROBERT G. VALLACE AND CHARLES H. SNYDER, OF MANSFIELD, OHIO.

DENTAL CHAlR.

v SEDLICIEICATIOIS forming part of Letters Patent No. 304,876, dated September 9, 1884.

Application filed December 6, 1852. (No model.)

To @ZZ whom it may concern:

Be it known that we, ROBERT G. VAL- Laon and Cnanrns H. Snvnnn, citizens of the United States, residing at Mansfield, in the county of Richland and State of Ohio, have invented certain new and useful Improvements in Dental Chairs 5 and we do hereby declare the following to bea full, clear, and exact description of the invention, such as will enable others skilled in the art to which `it apper tains to make and use the same. p

The invention has relationto improvements in dental chairs, and it consists in a chair of novel construction, which is adjustable in all its parts, whereby it may be arranged to suit the convenience of and facilitate the treatment by the operator. A Referring to the accompanying drawings, Figure l is a central vertical longitudinal section ofthe chair. Fig. 2 is a section through the line x x. Fig. 3 is a top view partly in section, of the foot-rest. Fig. 4 is a detached viewv ofthe pawl-and-ratch et mechanism which suspends the chairin any fixed position. Fig. is a detached bottom perspective view lool;- ing from front to rear, and showing the relative arrangement of the parts N O. Fig. 6 is an enlarged detached view illustrating the pinion M, pawl and ratehetl J, and other elements. j,

In the drawings, A denotes the seat of the. chair having a back, B, of the nature and con struction hereinafter described, and having also an adjustable means for elevating or depressing it according to circumstances, an adjustable foot-rest being also supplied, as hereinafter set forth.

Beneath the seat A, at opposite sides, are secured the bearing boxes a, in which is mounted a transverse axle, B', to the central parts of which is cast or otherwise secured the pivot C, having a head at its upper endfits lower porti ons exten ding into the sliding standard D, whiclris arranged to have a vertical movement in the hollow cylinder E. The cylinder E is sustained by means of the legs F, and may be cast with them if desired. The

sliding standard D is a plain shaft cast on one side with a series of ratchet-teeth, b, and being hollow to receive the contracted portion ofthe pivot C.

At the upper end of the cylinder B is provided the transverse journal-box G, in which the shaft d has its bearings. The shaft d projects outward a suitable distance beyond the edge of the Acylinder B, and is provided with a crank, H, by which it may be operated.

Upon the outer portions of the shaft d, immediately adjacent to the said journal-box G, is secured the .ratchet-wheel e, beyond which, also secured upon the shaft, is the sliding cam f, which receives its movement through the rod 7L, to which it is connected by the pin j. The outer portion of the shaft el is made hollow, to receive the rod 7i, and at m the shaft is slotted, whereby a pin may be made to connect the sliding cam f with the rod le., and the sliding movement thus permit-ted.

Upon the upper portion of the hollow cylinder E is pivoted a spring-pawl, I, which engages the ratchet-wheel e, and in the upper end of which is secured one end of the bent rod or lever J, the free end of which terminates in near relation to the inclined surface of the sliding camf. A pinion-wheel, M, is secured upon the shaft d in suitable relation to the rack Z), to engage it when the shaft is rotated by the crank H. l

XVe have described above the mechanism whereby the chair maybe adjusted vertically, and the operation of this part of the invention is as follows: If it is desired to depress the chair, the attendant draws the rod h outward. This has the effect of sliding the cani f outward, and the inclined surface of the said cam, coming in contact with the free end of the bent rod or lever J operates to elevate the pawl I from the ratchet e, at which time the chair may be lowered by turning the crank Hte the left. rlhe movement of the crank H is communicated to the wheel M through the shaft d, the wheel operating to force the sliding standard supporting the chair upward by its engagement with the toothed rack b.

rlhe chair may be inclined toward the front or rear upon the axle B at will, and may be sustained in any set inclination bythe engagement of the notches 1; in the lever N, rigidly connected with said axle, with the edge of the lever O, as indicated in Figs. l and 5. The outer lingers, S, formed on the upper and lower extremities of the notched edge of the lever N, are for the purpose of preventing the entire disengagement ot' the lever O from the lever N. The said ngers 8 therefore operate as a safeguard against the chair seat and back ever turning backward sufficiently to unseat the patient, even should the operator fail to give the engaging-levers N 0 any attention, or be careless in their adjustment when inclining the chair back and seat. The lever O is pivoted in the box 9, and its front end has a limited movement in the box l0, which assists, also, in preventing the lever O from becoming entirely disengaged from the lever N.

From the front edge ofthe seat of the chair depend downward at opposite corners the bars I, having horizontal sections Q on their lower ends, which sections are grooved on their sides, as indicated by dotted line, to receive the side bars, B, ot' the foot-rest attachment. These side bars extend forward a proper distance, and are capable of asliding movement in the grooves oi' the sections Q, whereby the foot-rest may be adj usted at will toward or from the chair. The front ends of the side bars, B, are provided with a bracket, S, upon which are secured the inclined racks T, which racks are covered with a cap, U, to prevent the foot-rest roller slipping from the machine.

V denotes the foot-rest roller, which is provided with a central axle, upon the outerends of which are secured the pinion-wheels W, which mesh with the racks T, whereby the footrest' roller may be moved Vupward or downward on the said racks, and adjusted to suit the pleasure of the attendant.

Upon one end of the central axle passing through thc foot-rest roller is secured, beyond the pinion-wheel WV, the pawl X, which is adapted to engage the teeth of the racks T at the proper time, and thus prevent the pinions W from moving after the foot-rest roller has been adj usted.

The portion Y of the back of the chair is properly padded, and is pivoted at a between the rear portions ofthe side arms of the chair, whereby it may be inclined to iit the back of the person sitting in the chair. r

In rear of the back portion, Y, and adjacent to the base thereof, is provided the pawland-ratchet mechanism Z, for locking the back Y in any position to which it may be adj usted.

The ratchet mechanism Z consists of the pivotcd rack a', secured to the back of the chair, the bracket b, secured to the lower rigid portion of the chair-seat and in which the rack moves, and the cam or eccentric c, whereby the rack is locked against vthe bracket and the back of the chair thus prevented from moving.

Upon the back Y is adjustably secured, by thumb-screws, the sliding section d', having at its upper end the horizontal slotted portion e.

In-the section d is adj ustably secured in the slot by set-serews, the adjustable shoulder-rest f, which may be moved vertically at will, and in the horizontal section cis secured upon the upper ends of the slotted side bars, G', the head-rest h. The side bars, G, are slotted, and through their slots are passed suitable setscrews, which also pass through the slots in the horizontal arm c', whereby the head-rest h may be secured toward or from the chair or swung in the are of a circle, according to the use to which it is to be ap plied. The rest f is longer than the rest h, andis adjustable with relation to the shoulders of the person in the chair, while the rest h is for the head alone. The lower part of the back of the patient is supported by the back Y, the shoulders by the rest f', and the head by the rest 7i.

It will be observed that the chair hereinbefore described is adj ustable in all its parts, whereby comfort is secured to the person using it, andthe treatment of the attendant is 9o facilitated.

Vhat/we claim as our invention, and desire to secure by Letters Patent, is-

l. In a chair,the cylinder E, mounted upon legs, aud the standard D, sustaining thc chairseat, and having a rack uponits side, in combination with the axle B, pinion M, pawl I, ratchet e, and means, substantially as described, for disengaging the pawl from theratchet when i desired.

2. The chair mounted upon the axle B, and having a pivot, (l, in combination with the sliding standard D, supplied with a rack on its side, the cylinder E, pinion M, axle B, pawl I, ratchet e, rod J, cam j", and rod h, substantially as set forth.

3. The chair-seat having at its front corners the bars l?, provided with horizontal sections Q, containing grooves, in combination with .the sides B, itted in said grooves, the brackets S, formed on the front ends of sides It, the inclined and covered racks T, supported by the loo IIO

brackets, the foot-rest roller V, having an I' ROBERT G. VALLACE.. CHARLES H. SNYDER.

Vitnesscs: f 'Y Tiros. E. BiiRRow, XV. S. BRADFORD. 

